363 
and Freshwater Deposits of Eastern Norfolk. 
beneath the black earth was covered up in June last, but ex- 
posed to view in March, and examined by Mr. Simons. 
Fig. 10. 
Runton Gap. 
a. Black earth with shells 1 
i. Reddish sand J 
c. Norwich crag in patches. 
freshwater. 
I shall now describe, first the freshwater beds and their 
fossils, and then the fossils of the subjacent layer of crag. 
The black earth is heavy and turns greenish when dried. It 
is sometimes divisible into layers, on the surface of which 
shells are seen in a compressed state ; but this is not always 
the case, the shells being often uninjured and irregularly di- 
spersed. Although the colour of this earth is doubtless due to 
vegetable matter, I have not found seeds in it, but occasionally 
small pieces of wood. The most shelly portions which I have 
seen were sent to me before my last visit to Norfolk, through 
the kindness of Robert Fitch, Esq., of Norwich. The red 
sand below resembles the crag in colour and contains the 
same shells, of which the following is a list, all of which 
have been examined by Mr. G. Sowerby: 1. Paludina vivi~ 
para. 2 . P.impura. 3 . Valvata piscinalis. 4 . Limnca pa- 
lustris. 5 . L. stagnalis, 6 . Planorbis imbricatus. 7 . P. 
albus. 8 . P. marginatus. 9 . Ancylus lacustris. 10 . Cyclas 
cornea. \\. C. appendicidata. C. amnica^veac.'^ Besides 
these is a small shell allied to Turbo ulvcc, but apparently 
different, of which I only procured one individual; also frag- 
ments of Anodon. Among these twelve species the only one 
which could not be identified with w^ell-known British living 
species is the Cyclas^ resembling C. amnica. It belongs to the 
sub-genus Pisidiurn^ and is remarkable, says Mr. G. Sowerby, 
“ for its great proportional altitude, in which respect it differs 
not only from the recent P. amnicum.^ but also from the fossil 
variety of P. amnicum, found at Grays in Essex. The concen- 
tric ridges on the outside of each valve are much more pro- 
minent than in the recent P. amnicum, particularly near the 
beaks, and in this circumstance they resemble the Grays fossil 
2 B 2 
